White as Frost by Anthea Sharp

SPFBO7

Two sisters. One enchanted forest. And a hidden destiny that could doom them both… Swept away to the castle beside the Darkwood, Rose Valrois finds herself in a world full of secrets and forbidden magic. There she meets her new stepsister, the enigmatic Princess Neeve, who will either become her best friend - or her worst enemy. When Rose follows her stepsister into the enchanted shadows beneath the trees, she is beset by dangerous creatures and rescued by Thorne, the Dark Elf guardian of the forest, who binds her to the Darkwood and forbids her to speak of its mysteries. Yet despite the danger surrounding her, Rose continues to risk everything in her quest for answers, until the day she steals into the depths of the forest and discovers the most perilous secret of all...

Young Adult • Fantasy/Mythic, Retelling, and Folklore